This article was originally published in the December 1969 issue of the magazine.

Mankind entered a new era at Tranquillity Base—an era in which travel will be reckoned not in thousands of miles but in millions and billions. Space is an endless frontier for our children, and for all future generations.

I believe that men will drive onward in the years ahead to Mars, to the moons of Jupiter, and to other new worlds in our vast solar system. Some of these destinations are attainable in this century, some even within the next two decades. If we give full rein to our growing space capabilities, we can rapidly establish a bridgehead in the heavens in the next dozen years.

In the mid-1970’s, for example, we could begin to assemble in earth orbit a permanent manned station. Gradually enlarged, it would become the work site of perhaps a hundred scientists.

In the late 1970’s we could establish on the moon a base camp that could be occupied for months or even years.

In the 1980’s we could send men to Mars—a voyage that would test our technology and equipment for travel to Venus and other planets later on.

In addition to these manned ventures, we will learn more about our solar system from unmanned probes. Several already are scheduled for the 1970’s. These include flights to orbit Mars, others to land there, flybys of Jupiter, and the first multiple-planet flight, for which the targets will be first Venus, then Mercury.

All these are exciting prospects. But they raise the most fundamental of questions: To what goals in space should we now commit ourselves as a Nation?

My own belief is that we should press forward vigorously with a balanced program—scientific and technological development as well as exploration. Of course our goals, and the pace at which we strive to attain them, must reflect our national will, and there are well-informed and reasonable men who feel we should proceed more slowly.

Rewards of Program Already Great

It has been said that we should concentrate all our resources on problems here at home. But I believe it would be a tragedy to foreclose our future in space. I believe our Nation can and must do these things simultaneously—not just one at a time.

Space exploration already has made life better on earth. Satellites, to mention just one development, have been of enormous benefit. They provide more accurate data to weather forecasters, aid mariners and aircraft pilots in fixing their positions, and give map makers hitherto unobtainable details of the earth’s surface. In the years ahead, they will find undiscovered mineral deposits and sources of fresh water; make global agricultural surveys and detect diseased crops; and even help in the fight against pollution of air and water.

And the conquest of space is everywhere lifting men’s horizons and spirits. Not only have global satellite communications brought nations closer, but—as Col. Frank Borman’s warm reception in the Soviet Union showed—space achievements are crossing the barriers that divide men on earth.

Although other targets will come within reach, the moon will occupy man for many years. The eight additional Apollo flights that are scheduled into 1973 will land our moon explorers in areas that are quite different geologically. Next March, Apollo 13 is scheduled to be launched toward a highland region, the Fra Mauro. Other Apollo destinations include supposedly volcanic peaks, rilles, and the craters Tycho and Copernicus.

We have other immediate tasks: to make space travel simpler, more reliable, and much cheaper. How can we achieve these goals?

First, we must develop re-usable rocket planes, able to shuttle hundreds of times between earth and earth orbit. Even a Volkswagen would be prohibitively expensive if we threw it away after each drive—and each Saturn V rocket costs $150,000,000.

Third, a permanent station in earth orbit would enable us to conduct needed research in many fields and would serve as an operations base for deep-space ventures.

Designers already can envision the reusable craft we will need to shuttle between earth and the orbiting space base. These large rocket planes would take off vertically from earth, fly to orbit, discharge their cargo, return to earth, and land horizontally, using wings, like conventional aircraft. They could carry a dozen passengers—physicists and astronomers, perhaps—into space. They could haul 10 tons of supplies and deploy and recover unmanned satellites. Similarly, re-usable nuclear shuttles would link the space base to a base in lunar orbit, and to other stations.

Research would be a major task in the earth-orbiting space station, with flight operations increasing as more men traveled outward from earth. Scientists would investigate the effects of zero gravity on men, animals, and plants; study the heavens without the interference of earth’s atmosphere; and develop new uses for earth-scanning satellites.

Nuclear Rockets to Probe Deep Space

Our first experiments with long stays for men in space are planned for 1972, using a laboratory built into the empty third stage of a Saturn rocket, a cylinder with as much room as a small bungalow. The first crew, three astronauts, will remain in orbit 28 days; later crews will stay 56 days. These missions will tell us more about man’s ability to work in space for long periods, and will help determine what kind of equipment and facilities the permanent space station should have.

Assembled from modules launched from earth, the permanent base would initially accommodate a crew of 12. As activities increased, other modules would be added.

The nuclear rocket promises to be the work horse of deep-space flight. At the NASA-Atomic Energy Commission test center in the Nevada desert, a prototype already has achieved twice the thrust per pound of fuel of our most powerful chemical rockets.

We call the prototype NERVA—nuclear engine for rocket vehicle application. Perhaps its most astonishing characteristic is its diminutive size; the reactor is no larger than a household refrigerator. Yet it generates more horsepower than Hoover Dam.

The nuclear rocket develops its great thrust by transferring the extreme heat of uranium fission—3,640 degrees F. in our prototype—to hydrogen propellant. The superheated hydrogen then exhausts at great velocity through the rocket’s nozzle. The rocket probably will be ready in the 1980’s for a manned trip to Mars and return—an odyssey that will span a year and eight months.

Although Mariners 6 and 7 provided us with a wealth of new data as they flew by Mars last summer, we still do not know if there is, or ever has been, life there. We expect to learn more from two additional Mariner spacecraft scheduled to orbit Mars in 1971, and from two unmanned Vikings which will attempt to soft-land instruments in 1973.

Every two years Mars swings into a favorable position for travel from earth. In the 1980’s, an excellent Mars launching date, or “window,” will open on October 3, 1983.

Two Craft Would Make Mars Voyage

Although NASA has no plans now for a manned voyage to Mars, the general procedure for a trip beginning on that date is clear. We would propel from earth orbit (to avoid radioactive contamination of the earth) two spacecraft about 250 feet long, each fitted with three nuclear rockets. Each would carry a crew of six—and some 1,800 meals per man. Two of the three rockets would be shed after launch and “parked” in space for reloading and future use.

On the 251-day journey to Mars, the two spacecraft would be joined nose to nose; thus one craft would be evacuated in case of trouble. A slow spinning motion would create centrifugal force to relieve the effects of weightlessness on the crew.

Separating, each ship would briefly retrofire its unused rocket, braking to enter Mars orbit, on June 9, 1984. The ships would remain for 80 days, each sending down a three-man laboratory for a month’s exploration on the surface.

Firing their rockets again to leave Mars, the two spacecraft would swing around Venus on the way home, letting the pull of that planet’s gravity hasten their homeward trip. On May 25, 1985, they would reach earth orbit, 601 days after leaving it. The crews would then catch the shuttle to earth—rather like men catching a bus home from work. The deep-space ships would remain in earth orbit; resupplied, they would be ready for a new voyage with a new crew.

What surprises would the astronauts bring home from Mars? No one can say—just as no one can say what explorers eventually may find on the moons of Jupiter, or on Pluto.

Such uncertainty inevitably attends the conquest of new horizons; explorers since the beginning of time have been unable to envision the full impact of their achievements.

Often, like Columbus, they made confident assessments which time proved wrong. It usually remained for those who followed to find the real significance of the explorer’s effort, and to reap benefits far greater than were anticipated. There is little doubt in my mind that the benefits of space travel will emerge in the same way.